Meiotic drive in natural populations of Drosophila melanogaster .5. On the nature of the SD region

Sandler, LH, Y.,  Genetics,  45:1671-1689. 1960.

Second chromosomes were collected from nature which, when heterozygous with a normal chromosome 1 in males, are present in functional sperm much more often than the expected 50 percent. This phenomenon, named segregation distortion, was found to depend on a locus named Segregation-distorter (symbolized SD), which is located near the centromere (and probably in the right arm) of chromosome 1